UNIX 下C編程 代碼01

//1string.c
#include <string.h>
#include <ctype.h>
char* format(char* str)
{//isupper,islower,isdigit,isspace,isblink,isalpha,...
	if(str==NULL||*str=='\0')
		return str;
	char* s = str;
	*str = toupper(*str);//tolower
	while(*++str)
		*str = tolower(*str);
	return s;
}
//1string.h
#ifndef _1STRING_
#define _1STRING_

char* format( char* str );

#endif
//2int.c
int bits(unsigned int d)
{
	int cnt=1;
	while(d>=10){
		d /= 10;
		cnt++;
	}
	return cnt;
}
//2int.h
#ifndef _2INT_
#define _2INT_

int bits(unsigned int d);

#endif
//3static.c
#include <stdio.h>
#include "1string.h"
#include "2int.h"
int main()
{
	char s[]="good morNinG, everyONe.";
	puts(format(s));
	printf("%d\n", bits(1234567));
	return 0;
}
//4so.c
#include <stdio.h>
#include "1string.h"
#include "2int.h"

int main()
{
	char s[]="hello";
	puts(format(s));
	printf("%d\n", bits(789));
	return 0;
}